# SPDX-FileCopyrightText: ☭ Emery Hemingway
# SPDX-License-Identifier: Unlicense


import preserves, syndicate, syndicate/relays
import ../schema/[config, sql]

{.passL: "-lpq".}

{.pragma: libpq, header: "libpq-fe.h", importc.}

type
  PGconn* {.libpq.} = ptr object
  ConnStatusType* {.libpq.} = enum
    CONNECTION_OK, CONNECTION_BAD, ##  Non-blocking mode only below here
                                 ##
                                 ##  The existence of these should never be relied upon - they should only
                                 ##  be used for user feedback or similar purposes.
                                 ##
    CONNECTION_STARTED,       ##  Waiting for connection to be made.
    CONNECTION_MADE,          ##  Connection OK; waiting to send.
    CONNECTION_AWAITING_RESPONSE, ##  Waiting for a response from the
                                 ##  postmaster.
    CONNECTION_AUTH_OK,       ##  Received authentication; waiting for
                       ##  backend startup.
    CONNECTION_SETENV,        ##  This state is no longer used.
    CONNECTION_SSL_STARTUP,   ##  Negotiating SSL.
    CONNECTION_NEEDED,        ##  Internal state: connect() needed
    CONNECTION_CHECK_WRITABLE, ##  Checking if session is read-write.
    CONNECTION_CONSUME,       ##  Consuming any extra messages.
    CONNECTION_GSS_STARTUP,   ##  Negotiating GSSAPI.
    CONNECTION_CHECK_TARGET,  ##  Checking target server properties.
    CONNECTION_CHECK_STANDBY  ##  Checking if server is in standby mode.


proc PQconnectdbParams(
    keywords: cstringArray; values: cstringArray; expand_dbname: cint): PGconn {.libpq.}

proc PQerrorMessage(conn: PGconn): cstring {.libpq.}
proc PQfinish(conn: PGconn) {.libpq.}
proc PQstatus(conn: PGconn): ConnStatusType {.libpq.}

# proc PQsocket(conn: PGconn): cint
# proc PQconnectStartParams(
#     keywords: cstringArray; values: cstringArray; expand_dbname: cint): PGconn
# TODO: async


type StringPairs = seq[tuple[key: string, val: string]]

proc splitParams(params: StringPairs): (cstringArray, cstringArray) =
  var strings = newSeq[string](params.len)
  for i, _ in params: strings[i] = params[i][0]
  result[0] = allocCStringArray(strings)
  for i, _ in params: strings[i] = params[i][1]
  result[1] = allocCStringArray(strings)

proc spawnPostgreActor*(turn: var Turn; root: Cap): Actor {.discardable.} =
  spawn("postgre", turn) do (turn: var Turn):
    during(turn, root, ?:PostgreArguments) do (params: StringPairs, ds: Cap):
      var
        conn: PGconn
        statusHandle: Handle
      block:
        var (keys, vals) = splitParams(params)
        conn = PQconnectdbParams(keys, vals, 0)
        deallocCStringArray(keys)
        deallocCStringArray(vals)
        if conn.isNil: raise newException(OutOfMemDefect, "failed to alloc PQ connection")
      let
        status = PQstatus(conn)
        msg = $PQerrorMessage(conn)
      statusHandle = publish(turn, ds,
          initRecord("status", toSymbol($status), msg.toPreserves))
      if status == CONNECTION_OK:
        discard
    do:
      PQfinish(conn)

when isMainModule:
  runActor("main") do (turn: var Turn; root: Cap):
    connectStdio(turn, root)
    spawnPostgreActor(turn, root)